The present invention relates to an air induction system which supplies air and fuel to the combustion chambers of an internal-combustion engine.
In such air induction systems, the size, shape and configuration of the air intake passage determines not only the efficiency with which intake air flows to the combustion chambers of the engine, but also the resonance frequency of the system. The latter parameter is important in particular when the engine is designed for resonance supercharging, in which case it is advantageous to provide an arrangement for modifying the resonance frequency of the system to adapt it to the operating speed of the engine. It is also important to make such air induction systems as simple and compact as possible, so as to reduce the space required for mounting, permitting greater latitude in the design of the automobile engine compartment
In a prior-art as disclosed in Japanese Patent-Laid Open No. Hei 4-175,465, the air induction system is compactly formed as a unit, with a collector section and a separate intake section. However, an injection valve, a throttle, an intake air flow sensor and an air inlet section are separately assembled. This arrangement is inferior with regard to assembly and mounting efficiency because the injection valve, the throttle, the intake air flow detector, and the air inlet section are assembled separately.
It is an object of the present invention to provide an air induction system for an internal-combustion engine in which an air inlet section, a collector section,and the engine intake ports, etc. are installed in compact form, for the purpose of decreasing the height of the engine to enable slanting a hood of a motor vehicle, thereby improving aerodynamic characteristics and fuel economy of the motor vehicle.